Combustion engines, such as diesel engines or Otto engines, are used in several types of applications and vehicles today, for example in heavy goods vehicles, such as trucks or buses, passenger cars, motor boats, vessels, ferries and ships. Combustion engines are also used in industrial engines and/or engine driven industrial robots, power plants such as e.g. electric power plants comprising a diesel generator, and in locomotives.
Combustion engines may be driven by diesel, petrol, or ethanol, or other types of biofuels. Such engines are is equipped with a fuel system to transport fuel from one or several fuel tanks to the internal combustion engine's injection system. The fuel system comprises one or several fuel pumps, which may be driven mechanically by the internal combustion engine, or be driven by an electric motor. The fuel pumps create a fuel flow and pressure to transport the fuel to the internal combustion engine's injection system, which supplies the fuel to the internal combustion engine's combustion chamber.
Fuel systems also comprise fuel filters for filtration of the fuel before it reaches the internal combustion engine's injection system. The internal combustion engine and its injection system are sensitive to impurities and may be negatively impacted if the fuel is too polluted. Impurities may mean solid particles, gas or liquid.
Some combustion engines or hybrid engines may be turned off when the vehicle stops, for example at a red light or in a traffic jam, with the objective of reducing fuel consumption and emissions. This function entails that the internal combustion engine is frequently started and stopped. When the internal combustion engine is turned off, the pressure in the fuel system drops drastically, since fuel no longer needs to be supplied to the internal combustion engine. On the other hand each start of the internal combustion engine requires a rapid pressure build-up in the fuel system, in order to quickly achieve sufficient supply of fuel to the internal combustion engine. Accordingly, frequent starts/stops of the internal combustion engine result in frequent pressure fluctuations in the fuel system, and therefore also in the fuel filter. During start of the internal combustion engine, and the resulting pressure increase in the fuel system, fuel is thus supplied via the fuel filter at a high pressure. The high pressure results in a risk that impurities in the fuel may be pressed through the filter, which may impact the functionality of the injection system and the internal combustion engine. Even if only a small amount of impurities reaches the internal combustion engine, the consequence may be that the internal combustion engine may not be driven by the fuel. Furthermore, there is a risk that the fuel filter may be damaged or collapse due to the pressure fluctuations and the high pressure that often has to be achieved in the system. The risk that the impurities may reach the internal combustion engine increases with the frequency of the fuel filter being subjected to a high pressure, as does the risk of damage to the fuel filter. It is thus desirable to lessen pressure fluctuations in the fuel filter.
Despite prior art solutions in this area, there remains a need to further develop a fuel system, which contributes to lessening pressure fluctuations in a fuel filter in a fuel system for an internal combustion engine, and which thus minimizes the risk of damage to the fuel filter and the internal combustion engine.